Post on 24-Dec-2021
I t d ti t t i l ti dIntroduction to terminology, tiered approach, specific protection goals and
linking exposure to effectsTheo Brock Alterra Wageningen UR (PPR Panel Member)Theo Brock, Alterra, Wageningen UR (PPR Panel Member)
1Info Session on Aquatic Guidance 6/7 November 2013
Terminology
• Prospective Risk Assessment– Evaluation of the probability of adverse effects of
plant protection product (PPP) exposure before the k ti l f th d tmarketing, release, or use of the product
→ Focus of Regulation (EC) No 1107/2009 and Aquatic Guidance DocumentGuidance Document
→ Evaluation of agricultural use of one active substance or one formulated product at a timeor one formulated product at a time
• Retrospective Risk AssessmentE l ti f th i t f i ti d/ t– Evaluation of the impact from existing and/or past releases of pesticides to the environment on basis of chemical and biological monitoring (e g Waterchemical and biological monitoring (e.g. Water Framework Directive) 2
Prospective aquatic risk assessment of PPPsof PPPs• Exposure assessment
– Calculation of time-dependent concentrations in the compartment water (and sediment)
– Predicted Environmental Concentrations (PECs) by means of FOCUS surface water scenarios and
d l d b i f d i lt l timodels and on basis of good agricultural practice
• Effect Assessment (focus of AGD)– Analysis of possible effects of predicted exposure on
aquatic organisms (individuals, populations, communities)
– Regulatory Acceptable Concentrations (RACs) by means of controlled ecotoxicity tests in lab and semi-field and models 3
Terminology
Acute (= short-term) effect assessment( )• Assessment of the RAC for adverse effects of
PPP exposure to (non-target) organismsPPP exposure to (non target) organisms occurring within a short period of exposure
Acute (= short-term) risk assessment• Comparing the RAC of the acute effect
assessment scheme with the appropriate PEC (usually peak concentration)
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TerminologyChronic (= long-term) effect assessment
A t f th RAC f d ff t f• Assessment of the RAC for adverse effects of PPP exposure to (non-target) that develop l l d/ h l l ti dslowly and/or have a long-lasting course, and
that are caused by short-term exposure (latency) l tor long-term exposure
Chronic (= long-term) risk assessmentChronic ( long term) risk assessment• Comparing the RAC of the chronic effect
assessment scheme with the appropriate PECassessment scheme with the appropriate PEC (may be peak or time-weighted average (TWA) concentration)concentration)
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Terminology
RACsw;ac or RACsw;ch
= Regulatory Acceptable Concentration for surface water (sw) within context of acute (ac) or chronic (ch) effect assessment scheme
PEC or PECPECsw;max or PECsw;twa
= Maximum (max) or time-weighted average (twa) P di t d E i t l C t ti f fPredicted Environmental Concentration for surface water (sw)
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Outline tiered approach
• All tiers within a decision h i t thscheme aim to assess the
same protection goal
• Lower tiers are moreLower tiers are more conservative
• Higher tiers aim at being more realistic
• Lower tiers require less effort than higher tierseffort than higher tiers
• Experimental higher tiers can be used to calibrate lower tiers
Separate schemes for acute and chronic effect assessment
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Separate schemes for acute and chronic effect assessment
Outline tiered approach
Focus of aquatic guidance document on experimental approaches
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Focus of aquatic guidance document on experimental approaches. Micro-/mesocosm studies (Tier 3) may be considered as surrogate reference tiers to calibrate lower tiers
Protection goals
Relationship between ptiers of effect assessment scheme and protection
lgoals
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Procedure used by PPR Panel
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Dimensions to define SPGs
Procedure to develop Specific Protection Goals (SPGs) for d f fi ld f tedge-of-field surface waters
Key drivers: microbes, algae, vascular plants, invertebrates, vertebrates
Ecol. entity: individual – (meta)population – functional group – ecosystem
Attribute: behaviour survival/growth abund /biomass process biodiversityAttribute: behaviour – survival/growth – abund./biomass – process – biodiversity
Magnitude: negligible effect – small effect – medium effect – large effect
Duration: days – weeks – months – seasons – > 1 year
Spatial scale: in crop – edge of field – nearby off-crop – watershed/landscapeSpatial scale: in crop edge of field nearby off crop watershed/landscape
Degree of certainty: high
Fixed in AGD
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SPGs: Two optionsEcological Threshold Option (ETO)
• Accepting only negligible effects on populations of aquatic• Accepting only negligible effects on populations of aquatic non-target organisms in edge-of-field
• Propagation of effects to the community ecosystem andPropagation of effects to the community, ecosystem and landscape will be less likely
• All tiers can address ETOAll tiers can address ETOEcological Recovery Option (ERO)
• Accepting some population level effects if ecological• Accepting some population level effects if ecological recovery takes place within an acceptable time
• Focus on vulnerable populations of aquatic organismsFocus on vulnerable populations of aquatic organisms• Reasonable option only if recovery is not hampered by
multi-stress of pesticidesp• ERO may be addressed by mesocosm experiments and
effect models12
ERO and vulnerability
General framework for ecological vulnerability assessment (after DeGeneral framework for ecological vulnerability assessment (after De Lange et al. 2010)
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Specific Protection Goals
Organism group Ecological Attribute Magnitude TimeEcological threshold option
g g p gentity
g
Algae population abundance/biomassbiomass
Aquatic plants populationsurvival/growthabundance/
negligible effect notapplicable
biomass
Aquaticinvertebrates population abundance/
biomassinvertebrates p p biomass
Vertebratesindividual survival
abundance/population abundance/biomass
Aquatic functional Processes (e.g. RA will not be developed since Tier 1 data requirements are
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Aquaticmicrobes
functionalgroup litter break
down)
Tier-1 data requirements are not defined
Specific Protection GoalsEcological recovery option
Organism Ecological Attribute Duration and magnitude of ggroup
gentity
geffect on sensitive and vulnerable populations
Algae population Abundance/Biomass
Total effect period < 8 weeks (also for repeated applications)
Usually not possible for vulnerable populations with long life cycles and low dispersal abilities
Aquatic plants populationSurvival/growthabundance/Biomass
Not leading to ecologically important indirect effects
Aquaticinvertebrates population abundance/
biomass
Vertebrates No recovery option
Aquatic functional RA will not be developed since
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Aquaticmicrobes
functionalgroup processes Tier-1 data requirements are not
defined
Linking exposure to effects
Ecotoxicologically relevant concentration (ERC)Ecotoxicologically relevant concentration (ERC)
• ERC is the exposure concentration that gives an i t l ti t t i l i l ff tappropriate correlation to ecotoxicological effects
• For a realistic to worst-case risk assessment theFor a realistic to worst case risk assessment the ‘C’ in the PEC estimate should not be in conflict with the ‘C’ in the RAC estimatewith the C in the RAC estimate
• In the AGD the freely dissolved chemical averaged over the water column (of ponds, ditches and streams) is chosen as the most
Crelevant ERC16
Linking exposure to effects
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PECsw;max and PECsw;twa in chronic risk assessmentrisk assessmentIn chronic risk assessments in first instance the PECsw;maxis used and under certain conditions the PEC (defaultis used, and under certain conditions the PECsw;twa (default 7 day time window) (Decision scheme section 4.5.2)Use of PEC t may not be appropriateUse of PECsw;twa may not be appropriate
When linked to RACs based on effect studies where the loss of the substance is fast and toxicity isthe loss of the substance is fast and toxicity is expressed in terms of initial concentration
When effect endpoint in the chronic test is based on aWhen effect endpoint in the chronic test is based on a developmental process during a specific life-cycle stageg
When the (acute L(E)C50/chronic NOEC) ratio is < 10
18If latency of effects has been demonstrated (or might be expected)
FOCUSsw exposure profiles(examples)(examples)
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Time-varying exposure regimes
• In edge-of-field surface waters time-variable exposure regimes are the rule rather than the exception
• Dynamics in predicted exposure concentrations considerably vary per exposure scenario and type of freshwater ecosystem (streams drainage ditches ponds)freshwater ecosystem (streams, drainage ditches, ponds)
• Implications of time-variable exposure profiles in relation to ecotoxicity (higher tier option)
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ecotoxicity (higher tier option)
Exposure in ecotoxicity studies
In higher tier tests the exposure regime selected should be realistic to
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In higher tier tests the exposure regime selected should be realistic to worst case relative to the predicted field exposure regime
Linking PECs and RACs
Particularly if the TWA approach cannot be applied in the
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risk assessment, refined ecotoxicological exposure studies may be a higher-tier option.
Selecting the appropriate exposure regime in higher-tier testsregime in higher tier tests
• Refined exposure laboratory tests (Tier 2C)• Model ecosystem approach (Tier 3)
Determine key parameters from the FOCUS exposure fil t i f fil th t h t b i l t d
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profile to inform exposure profiles that have to be simulated in ecotoxicological effects studies.
Selecting the appropriate exposure regime in higher-tier testsregime in higher tier tests
Are pulses above the Tier 1 threshold level toxicologically and/or ecologically independent?
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Thank you !
25Info Session on Aquatic Guidance 6/7 November 2013